Apparatuses and methods for manipulating curved sheets

ABSTRACT

In one aspect of the disclosure, an apparatus for manipulating a plurality of curved sheets is provided. Each of the plurality of curved sheets includes an upper surface and a lower surface. The apparatus includes tooling to be coupled to the upper surface of each of the plurality of curved sheets. The tooling is capable of moving the plurality of curved sheets relative to each other and abutting the plurality of curved sheets so that the upper surface of each of the plurality of curved sheets is coextensive with a virtual arcuate surface. The apparatus also includes a welding apparatus capable of welding the plurality of curved sheets together after abutting the plurality of curved sheets.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of co-pending U.S. patent applicationSer. No. 13/965,572, filed Aug. 13, 2013. The aforementioned relatedpatent application is herein incorporated by reference in its entirety.

BACKGROUND

Curved sheets are conventionally coupled together by overlapping edgesof the curved sheets to form lap joints, fastened together, e.g., withrivets. Curved sheets are commonly coupled in this manner in aerospaceapplications and, in such an example, the curved sheets are metalliccurved sheets and may form, e.g., part of a fuselage, a wing, astabilizer or other aerodynamic surface. Using lap joints and/or spliceplates when coupling curved sheets together requires additional materialto provide overlap of the curved sheets, thereby increasing the weightand cost of the assembly.

SUMMARY

Accordingly, apparatuses and methods that reduce the cost ofmanufacturing of assemblies of curved sheets and the weight of suchassemblies are desired.

One example of the present disclosure relates to an apparatus formanipulating a plurality of curved sheets. Each of the plurality ofcurved sheets includes an upper surface and a lower surface. Theapparatus includes tooling to be coupled to the upper surface of each ofthe plurality of curved sheets. The tooling is capable of moving theplurality of curved sheets relative to each other and abutting theplurality of curved sheets so that the upper surface of each of theplurality of curved sheets is coextensive with a virtual arcuatesurface.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the virtual arcuate surface includes no inflection points along across-section thereof perpendicular to a virtual straight linecoextensive with the virtual arcuate surface.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the plurality of curved sheets, abutted so that the upper surface ofeach of the plurality of curved sheets is coextensive with the virtualarcuate surface, subtend a central angle between about 2 degrees andabout 270 degrees in a virtual plane perpendicular to a virtual straightline coextensive with the virtual arcuate surface.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the plurality of curved sheets, abutted so that the upper surface ofeach of the plurality of curved sheets is coextensive with the virtualarcuate surface, subtend a central angle of about 180 degrees in avirtual plane perpendicular to a virtual straight line coextensive withthe virtual arcuate surface.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the tooling includes at least one holder to be removably coupled to theupper surface of at least one of the plurality of curved sheets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the at least one holder extends in a non-perpendicular directionrelative to weight vectors of the plurality of curved sheets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the at least one holder extends in a substantially parallel directionrelative to weight vectors of the plurality of curved sheets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the at least one holder extends in a substantially perpendiculardirection relative to weight vectors of the plurality of curved sheets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the at least one holder has a selectively variable length.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the tooling includes at least one first holder and at least one secondholder.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the at least one first holder and the at least one second holder extendin different directions.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the tooling is reconfigurable.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a processing station facing the lower surfaces of theplurality of curved sheets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the processing station includes a subtractive-manufacturing apparatus.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the subtractive-manufacturing apparatus includes a drilling apparatus.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the processing station includes a laser-welding apparatus.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a carriage configured to move relative to the plurality ofcurved sheets and the processing station is coupled to and moveable withthe carriage.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the processing station includes a friction-stir-welding apparatus.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a first magnetic member to be associated with the uppersurface of a first curved sheet of the plurality of curved sheetsadjacent an edge of the first curved sheet, a second magnetic member tobe associated with the lower surface of the first curved sheet adjacentthe edge of the first curved sheet, a third magnetic member to beassociated with the upper surface of a second curved sheet of theplurality of curved sheets adjacent an edge of the second curved sheet,and a fourth magnetic member to be associated with the lower surface ofthe second curved sheet adjacent the edge of the second curved sheet.The first magnetic member is to be magnetically coupled to the secondmagnetic member and the third magnetic member is to be magneticallycoupled to the fourth magnetic member with the edge of the first curvedsheet and the edge of the second curved sheet abutting each other.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a flexible joining member to be installed between thefirst magnetic member and the third magnetic member or between thesecond magnetic member and the fourth magnetic member to provide acoupling between the first curved sheet and the second curved sheet withthe edge of the first curved sheet and the edge of the second curvedsheet abutting each other.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a decoupling member rotatably attached to thefriction-stir-welding apparatus to eliminate the coupling provided bythe flexible joining member between the first curved sheet and thesecond curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the decoupling member decouples the flexible joining member from thefirst curved sheet and the second curved sheet while the first curvedsheet and the second curved sheet are welded together by thefriction-stir-welding apparatus.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the decoupling member translates but does not rotate relative to thefirst curved sheet and the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the decoupling member is to be at least partially positioned in a spacebetween the first magnetic member and the third magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the decoupling member is to move along the space and is at leastpartially retained in the space by the first magnetic member and thethird magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the decoupling member movably engages at least one of the first magneticmember and the third magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the friction-stir-welding apparatus is to be at least partiallypositioned in the space.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a rigid joining member to be coupled to the first curvedsheet and to the second curved sheet with the edge of the first curvedsheet and the edge of the second curved sheet abutting each other. Therigid joining member includes a curvature.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a carriage configured to move relative to the first curvedsheet and the second curved sheet. The friction-stir-welding apparatusis coupled to and moveable with the carriage.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the second magnetic member and fourth magnetic member are coupled to andare moveable with the carriage. The first magnetic member and thirdmagnetic member remain stationary relative to the plurality of curvedsheets.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a first magnetic member to be associated with the uppersurface of one of the plurality of curved sheets adjacent an edge of theone of the plurality of curved sheets and a second magnetic member to beassociated with the lower surface of one of the plurality of curvedsheets adjacent an edge of the one of the plurality of curved sheets.The first magnetic member is to be magnetically coupled to the secondmagnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first magnetic member and the second magnetic member are to beassociated with a same one of the plurality of curved sheets.

One example of the present disclosure relates to an apparatus forconstraining an edge of a first curved sheet and an edge of a secondcurved sheet. The apparatus includes a first magnetic member to beassociated with an upper surface of the first curved sheet, a secondmagnetic member to be associated with a lower surface of the firstcurved sheet, a third magnetic member to be associated with an uppersurface of the second curved sheet, and a fourth magnetic member to beassociated with a lower surface of the second curved sheet. The firstmagnetic member is to be magnetically coupled to the second magneticmember and the third magnet member is to be magnetically coupled to thefourth magnetic member with the edge of the first curved sheet and theedge of the second curved sheet abutting each other.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first magnetic member and the second magnetic member conform to thefirst curved sheet, and the third magnetic member and the fourthmagnetic member conform to the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples, atleast two of the first magnetic member, the second magnetic member, thethird magnetic member, and the fourth magnetic member have a compliantshape.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first curved sheet and the second curved sheet are curved metallicsheets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first magnetic member and the second magnetic member are locatedadjacent the edge of the first curved sheet, and the third magneticmember and the fourth magnetic member are located adjacent the edge ofthe second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first magnetic member, the second magnetic member, the thirdmagnetic member, and the fourth magnetic member comprise permanentmagnets.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,one of the first magnetic member and the second magnetic membercomprises a permanent magnet and another of the first magnetic memberand the second magnetic member comprises a ferromagnetic material, andone of the third magnetic member and the fourth magnetic membercomprises a permanent magnet and another of the third magnetic memberand the fourth magnetic member comprises a ferromagnetic material.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples, atleast one of the first magnetic member and the second magnetic membercomprises an electro-magnet, and at least one of the third magneticmember and the fourth magnetic member comprises an electro-magnet.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a joining member to be coupled to the first curved sheetand the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the joining member is a flexible joining member to be installed betweenone of the first magnetic member and the third magnetic member or thesecond magnetic member and the fourth magnetic member to provide acoupling between the first curved sheet and the second curved sheet withthe edge of the first curved sheet and the edge of the second curvedsheet abutting each other.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the flexible joining member is to be installed between the firstmagnetic member and the third magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the flexible joining member is to be installed between the secondmagnetic member and the fourth magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the flexible joining member includes adhesive on at least a portionthereof, and the flexible joining member is to be coupled to the firstcurved sheet and the second curved sheet with the adhesive.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the adhesive is located on the joining member adjacent a first edge anda second edge of the joining member. The first edge and the second edgeoppose one another, with the first edge to be adhesively coupled to thefirst curved sheet and the second edge to be adhesively coupled to thesecond curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the flexible joining member includes a portion lacking adhesive. Theportion lacking adhesive is between the first edge and the second edgeof the flexible joining member and is to at least partially overlap theedge of the first curved sheet and the edge of the second curved sheet,with the edge of the first curved sheet and the edge of the secondcurved sheet abutting each other.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the joining member is a rigid joining member to be coupled to the firstcurved sheet and the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the rigid joining member is to be coupled to the upper surface of thefirst curved sheet and the upper surface of the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the rigid joining member is to be coupled to the lower surface of thefirst curved sheet and the lower surface of the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the rigid joining member includes a slot.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the rigid joining member is curved.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the joining member is a first joining member. The apparatus alsoincludes a second joining member that is to be coupled to the firstcurved sheet and the second curved sheet, with the edge of the firstcurved sheet and the edge of the second curved sheet abutting eachother.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first joining member is a rigid joining member and the secondjoining member is a flexible joining member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples, aspace is to be provided between the first magnetic member and the thirdmagnetic member. The apparatus also includes a joining member to becoupled to the first curved sheet and the second curved sheet and toextend at least partially across the space between the first magneticmember and the third magnetic member.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes a carriage configured to move relative to the first curvedsheet and the second curved sheet. The second magnetic member and thefourth magnetic member are coupled to the carriage.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the second magnetic member and the fourth magnetic member are to movewith the carriage relative to the first curved sheet and the secondcurved sheet, and the first magnetic member and the third magneticmember remain stationary relative to the first curved sheet and thesecond curved sheet.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the apparatusalso includes at least one friction-reducing member. At least a portionof the at least one friction-reducing member is between at least one ofthe second magnetic member and the fourth magnetic member and at leastone of the first curved sheet and the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the friction-reducing member is a wheel.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples, aspacing between a portion of the at least one of the second magneticmember and the fourth magnetic member and the at least one of the firstcurved sheet and the second curved sheet is maintained with the frictionreducing member engaging at least one of the first curved sheet and thesecond curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the friction-reducing member is a layer of material applied to a surfaceof one of the second magnetic member and the fourth magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first magnetic member includes a substrate configured to engage theupper surface of the first curved sheet and the third magnetic memberincludes a substrate configured to engage the upper surface of thesecond curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the substrate of the first magnetic member is to conform to the firstcurved sheet and the substrate of the third magnetic member is toconform to the second curved sheet.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the substrate of the first magnetic member and the substrate of thethird magnetic member are flexible.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first magnetic member includes a plurality of magnetic tiles coupledto the substrate of the first magnetic member, and the third magneticmember includes a plurality of magnetic tiles coupled to the substrateof the third magnetic member.

In one example of the apparatus, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the plurality of magnetic tiles coupled to the substrate of the firstmagnetic member are spaced apart from one another, and the plurality ofmagnetic tiles coupled to the substrate of the third magnetic member arespaced apart from one another.

One example of the present disclosure relates to a vehicle including asubstructure and a weldment coupled to the substructure. The weldmentincludes a first sheet, a second sheet, and a butt weld between thefirst sheet and the second sheet. The butt weld is formed before theweldment is coupled to the substructure.

In one example of the vehicle, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the vehicle is an airplane.

In one example of the vehicle, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the substructure is at least a portion of a frame of the airplane. Thefirst sheet is one of a first metallic fuselage sheet, a first metallicwing sheet, and a first metallic stabilizer sheet. The second sheet is asecond metallic fuselage sheet, a second metallic wing sheet, and asecond metallic stabilizer sheet.

In one example of the vehicle, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the first sheet is a first metallic sheet and the second sheet is asecond metallic sheet.

One example of the present disclosure relates to a method ofmanufacturing an assembly including a first curved sheet and a secondcurved sheet. The first curved sheet includes a first upper surface anda first edge. The second curved sheet includes a second upper surfaceand a second edge. The method includes supporting the first uppersurface and the second upper surface, abutting the first edge and thesecond edge so that the first upper surface and the second upper surfaceare coextensive with a virtual arcuate surface, and welding the firstedge and the second edge together to create a weldment after abuttingthe first edge and the second edge.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the virtual arcuate surface includes no inflection points along across-section thereof perpendicular to a virtual straight linecoextensive with the virtual arcuate surface.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes reconfiguring tooling supporting the first upper surfaceand the second upper surface.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes positioning a processing station to face a first lowersurface of the first curved sheet and a second lower surface of thesecond curved sheet.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes moving the processing station relative to the first curvedsheet and the second curved sheet.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,positioning the processing station includes positioning afriction-stir-welding apparatus to face the first lower surface and thesecond lower surface.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes locating a first magnetic member relative to the firstupper surface adjacent the first edge, locating a second magnetic memberrelative to the first lower surface adjacent the first edge, locating athird magnetic member relative to the second upper surface adjacent thesecond edge, locating a fourth magnetic member relative to the secondlower surface adjacent the second edge, and magnetically coupling thefirst magnetic member to the second magnetic member and the thirdmagnetic member to the fourth magnetic member after abutting the firstedge and the second edge.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes coupling a flexible joining member to the first curvedsheet and to the second curved sheet between at least one of the firstmagnetic member and the third magnetic member or the second magneticmember and the fourth magnetic member after abutting the first edge andthe second edge.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes decoupling the flexible joining member from the firstcurved sheet and the second curved.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,decoupling further includes decoupling the flexible joining member fromthe first curved sheet and the second curved sheet while welding thefirst edge and the second edge.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes rotatably coupling a decoupling member to thefriction-stir-welding apparatus.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes coupling a rigid joining member to the first curved sheetand the second curved sheet after abutting the first edge and the secondedge. The rigid joining member includes a curvature.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes moving the friction-stir-welding apparatus relative to thefirst curved sheet and the second curved sheet.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes moving the second magnetic member and fourth magneticmember relative to the first curved sheet and the second curved sheet.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes locating a first magnetic member relative to at least oneof the first upper surface and the second upper surface adjacent atleast one of the first edge and the second edge, locating a secondmagnetic member relative to at least one of a first lower surface of thefirst curved sheet and a second lower surface of the second curved sheetadjacent at least one of the first edge and the second edge, andmagnetically coupling the first magnetic member to the second magneticmember.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes locating the first magnetic member and the second magneticmember relative to a same one of the first curved sheet and the secondcurved sheet.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes providing a space between the first edge and the secondedge. The space is sufficient to process at least one of the first edgeand the second edge. The method also includes processing at least one ofthe first edge and the second edge.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,abutting the first edge and the second edge occurs subsequent toprocessing at least one of the first edge and the second edge.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,supporting the first upper surface and the second upper surface furtherincludes coupling tooling to the first upper surface and the secondupper surface.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes moving the first curved sheet and the second curved sheetrelative to each other with the tooling.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,abutting further includes abutting the first edge and the second edgewith the tooling.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes coupling the weldment to a structure.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,the structure is at least a portion of a frame of an aircraft.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes processing the weldment.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,processing the weldment includes performing gauge reduction on at leasta portion of the weldment.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,processing the weldment includes reducing the thickness of at least aportion of the weldment.

In one example of the method, which may include at least a portion ofthe subject matter of any of the preceding and/or following examples,processing the weldment includes trimming at least a portion of theweldment.

In one example, which may include at least a portion of the subjectmatter of any of the preceding and/or following examples, the methodalso includes constraining the first edge and the second edge subsequentto abutting the first edge and the second edge and prior to welding.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described examples of the disclosure in general terms,reference will now be made to the accompanying drawings, which are notnecessarily drawn to scale, and wherein like reference charactersdesignate the same or similar parts throughout the several views, andwherein:

FIG. 1 is a flow diagram of aircraft production and service methodology;

FIG. 2 is a block diagram of an aircraft;

FIG. 3 is a perspective view of a portion of a vehicle such as, forexample, an aircraft, according to an aspect of the present disclosure.

FIG. 4 is a block diagram of an apparatus, according to an aspect of thepresent disclosure;

FIG. 5 is a schematic elevational view of an apparatus including toolingfor supporting a plurality of curved sheets, according to an aspect ofthe present disclosure;

FIG. 6 is an elevational view of the apparatus shown in FIG. 5,according to an aspect of the present disclosure;

FIG. 7 is a schematic elevational view of the apparatus shown in FIG. 5,according to an aspect of the present disclosure;

FIG. 8 is a schematic elevational view of an apparatus including toolingfor supporting a plurality of curved sheets, according to an aspect ofthe present disclosure;

FIG. 9 is a schematic elevational view of an apparatus, according to anaspect of the present disclosure;

FIG. 10 is a schematic top view of a portion of the apparatus shown inFIG. 9, according to an aspect of the present disclosure;

FIG. 11 is a schematic side view of a portion of the apparatus shown inFIG. 10, according to an aspect of the present disclosure;

FIG. 12 is a schematic elevational view of an apparatus, according to anaspect of the present disclosure;

FIG. 13 is a schematic top view of a portion of the apparatus shown inFIG. 12, according to an aspect of the present disclosure;

FIG. 14 is a schematic elevational view of a portion of the apparatusshown in FIGS. 12 and 13, according to an aspect of the presentdisclosure;

FIG. 15 is a block diagram of an apparatus, according to an aspect ofthe present disclosure;

FIG. 16 is a block diagram of a vehicle, according to an aspect of thepresent disclosure; and

FIG. 17 is a schematic elevational view of a portion of a friction-stirwelding apparatus, according to an aspect of the present disclosure.

DETAILED DESCRIPTION

Examples of the disclosure may be described in the context of anaircraft manufacturing and service method 100 as shown in FIG. 1 and anaircraft 102 as shown in FIG. 2. During pre-production, exemplary method100 may include specification and design 104 of the aircraft 102 andmaterial procurement 106. During production, component and subassemblymanufacturing 108 and system integration 110 of the aircraft take place.Thereafter, the aircraft 102 may go through certification and delivery112 to be placed in service 114. While in service by a customer, theaircraft 102 is scheduled for routine maintenance and service 116 (whichmay also include modification, reconfiguration, refurbishment, and soon).

Each of the processes of the illustrative method 100 may be performed orcarried out by a system integrator, a third party, and/or an operator(e.g., a customer). For the purposes of this description, a systemintegrator may include, without limitation, any number of aircraftmanufacturers and major-system subcontractors; a third party mayinclude, without limitation, any number of vendors, subcontractors, andsuppliers; and an operator may be an airline, leasing company, militaryentity, service organization, and so on.

As shown in FIG. 2, the aircraft 102 produced by the illustrative method100 may include an airframe 118 with a plurality of high-level systems120 and an interior 122. Examples of high-level systems 120 include oneor more of a propulsion system 124, an electrical system 126, ahydraulic system 128, and an environmental system 130. Any number ofother systems may be included. Although an aerospace example is shown,the principles of the disclosure may be applied to other industries,such as the automotive industry.

Apparatus and methods shown or described herein may be employed duringany one or more of the stages of the manufacturing and service method100. For example, components or subassemblies corresponding to componentand subassembly manufacturing 108 may be fabricated or manufactured in amanner similar to components or subassemblies produced while theaircraft 102 is in service. Also, one or more aspects of the apparatus,method, or combination thereof may be utilized during the productionstates 108 and 110, for example, by substantially expediting assembly ofor reducing the cost of an aircraft 102. Similarly, one or more ofapparatus or method realizations, or a combination thereof, may beutilized, for example and without limitation, while the aircraft 102 isin service, e.g., maintenance and service 116.

With reference to FIG. 3, one example of the disclosure relates to avehicle 200, such as an aircraft 200 (a portion thereof shown in FIG.3). The vehicle 200 may include a substructure 206 and a plurality ofsheets 208. The substructure 206 may be at least a portion of a frame204 of the vehicle 200 and the plurality of sheets 208 may be curved.The plurality of sheets 208 may also be metallic.

Referring now to FIGS. 4-8, one example of the present disclosurerelates to an apparatus 212 for manipulating the plurality of curvedsheets 208. Each of the plurality of curved sheets 208 includes an uppersurface 216 and a lower surface 220. In one example, an upper surface216 is a surface that is to be directly impinged by virtual verticalvectors 224 (see FIG. 6) originating from above the curved sheet 208 anddirected downward, and a lower surface 220 is a surface that is to bedirectly impinged by virtual vertical vectors 228 (see FIG. 6)originating from below the curved sheet 208 and directed upward. Theapparatus 212 also includes tooling 232 to be coupled to the uppersurface 216 of each of the plurality of curved sheets 208. The tooling232 is capable of moving the plurality of curved sheets 208 relative toeach other and abutting the plurality of curved sheets 208 so that theupper surface 216 of each of the plurality of curved sheets 208 iscoextensive with a virtual arcuate surface 236 (see FIGS. 6 and 7). Theapparatus 212 may manipulate any number of curved sheets 208. In oneexample illustrated in FIGS. 5-7, the apparatus 212 manipulates threecurved sheets 208. In another example illustrated in FIG. 8, theapparatus 212 manipulates four curved sheets 208. No matter the numberof curved sheets 208, the tooling 232 of the apparatus 212 is capable ofmoving the plurality of curved sheets 208 relative to each other andabutting the plurality of curved sheets 208 so that the upper surface216 of each of the plurality of curved sheets 208 is coextensive with avirtual arcuate surface 236 (see FIG. 5).

Referring, for example, to FIG. 5, the virtual arcuate surface 236includes no inflection points along a cross-section thereofperpendicular to a virtual straight line coextensive with the virtualarcuate surface 236. As used herein, an inflection point is a locationalong a contour where a curvature of the contour changes from concave toconvex or vice versa.

With continued reference to FIGS. 6 and 7, in one example, the pluralityof curved sheets 208, abutted so that the upper surface 216 of each ofthe plurality of curved sheets 208 is coextensive with the virtualarcuate surface 236 (see FIG. 5), subtend a central angle between about2 degrees and about 270 degrees in a virtual plane perpendicular to avirtual straight line coextensive with the virtual arcuate surface 236.In one example, the plurality of curved sheets 208, abutted so that theupper surface 216 of each of the plurality of curved sheets 208 iscoextensive with the virtual arcuate surface 236, subtend a centralangle of about 180 degrees in a virtual plane perpendicular to a virtualstraight line coextensive with the virtual arcuate surface 236. Thevirtual arcuate surface 236, in some example, may form part or all of acircle, while in other examples, the virtual arcuate surface 236 mayapproximate a shape of a circle, and in still other examples, thevirtual arcuate surface 236 may form part or all of any arcuate shape.Thus, the curved sheets 208 may subtend a central angle associated witha circle, an approximation of a circle, or any other arcuate shape.

Referring to FIGS. 4-8, in one example, the tooling 232 includes atleast one holder 240, 243, 245 to be removably coupled to the uppersurface 216 of at least one of the plurality of curved sheets 208. Thetooling 232 may be removably coupled to at least one of the plurality ofcurved sheets 208 in a variety of ways and all of such possibilities areintended to be within the spirit and scope of the present disclosure. Inone example, the tooling 232 may include one or more suction cups 241 incommunication with a vacuum source 242. The vacuum source 242 providessufficient vacuum pressure to the one or more suction cups 241 to securethe at least one of the plurality of curved sheets 208 to the tooling232. The vacuum source 242 may be selectively activated and deactivatedto respectively supply and interrupt vacuum pressure to the suction cups241, thereby selectively coupling and uncoupling the tooling 232 to theat least one of the plurality of curved sheets 208. In one example, theat least one holder 243 may extend in a non-perpendicular directionrelative to weight vectors 244 (see FIG. 5) of the plurality of curvedsheets 208. In one example, the at least one holder 243 may extend in asubstantially parallel direction relative to weight vectors 244 of theplurality of curved sheets 208. In one example, the at least one holder240 may extend in a substantially perpendicular direction relative toweight vectors 244 of the plurality of curved sheets 208. The at leastone holder 240 has a selectively variable length.

With continued reference to FIGS. 4-8, in one example, the tooling 232includes at least one first holder 240 and at least one second holder243. The at least one first holder 240 and the at least one secondholder 243 extend in different directions. In one example, tooling 232also includes at least one third holder 245. In one aspect, the thirdholder 245 may extend in a similar direction to one of the first holder240 and the third holder 243. In another aspect, the third holder 245may extend in a different direction than the first holder 240 and thesecond holder 243. The tooling 232 is reconfigurable. Reconfigurabletooling 232 is adjustable to accommodate sheets 208 of varying shapes,sizes, and configurations, as opposed to hard tooling, which has a fixedshape (i.e., not adjustable) and is configured to accommodate only asingle shape or configuration of sheets.

Continuing to refer to FIGS. 4-8, in one example, the apparatus 212 alsoincludes a processing station 248 facing the lower surfaces 220 of theplurality of curved sheets 208. In one aspect, the processing station248 includes a subtractive-manufacturing apparatus 249. Thesubtractive-manufacturing apparatus 249 may include a drilling apparatus250. In another aspect, the processing station 248 includes alaser-welding apparatus 251.

With reference to FIGS. 4-8, in one example, the apparatus 212 alsoincludes a carriage 288 configured to move relative to the plurality ofcurved sheets 208 and the processing station 248 is coupled to andmoveable with the carriage 288. The processing station 248 may include afriction-stir-welding apparatus 247. One example of a friction-stirwelding apparatus 247 is illustrated in FIG. 17.

With continued reference to FIG. 4 and additional reference to FIGS.9-11, the apparatus 212 also includes a first magnetic member 252 to beassociated with the upper surface 216 of a first curved sheet 208adjacent an edge 256 of the first curved sheet 208, a second magneticmember 260 to be associated with the lower surface 220 of the firstcurved sheet 208 adjacent the edge 256 of the first curved sheet 208, athird magnetic member 264 to be associated with the upper surface 216 ofa second curved sheet 208 adjacent an edge 256 of the second curvedsheet 208, and a fourth magnetic member 268 to be associated with thelower surface 220 of the second curved sheet 208 adjacent the edge 256of the second curved sheet 208. The first magnetic member 252 is to bemagnetically coupled to the second magnetic member 260 and the thirdmagnetic member 264 is to be magnetically coupled to the fourth magneticmember 268 with the edge 256 of the first curved sheet 208 and the edge256 of the second curved sheet 208 abutting each other.

Referring now to FIGS. 4, 12 and 13, in one example, the apparatus 212also includes a flexible joining member 272 to be installed between thefirst magnetic member 252 and the third magnetic member 264 or betweenthe second magnetic member 260 and the fourth magnetic member 268 toprovide a coupling between the first curved sheet 208 and the secondcurved sheet 208 with the edge 256 of the first curved sheet 208 and theedge 256 of the second curved sheet 208 abutting each other. In theillustrated example, the flexible joining member 272 is installedbetween the first magnetic member 252 and the third magnetic member 264.

With reference to FIGS. 4 and 12-14, in one example, the apparatus 212also includes a decoupling member 276 (see FIG. 14) rotatably attachedto the friction-stir-welding apparatus 247 to eliminate the couplingprovided by the flexible joining member 272 between the first curvedsheet 208 and the second curved sheet 208. The decoupling member 276decouples the flexible joining member 272 from the first curved sheet208 and the second curved sheet 208 while the first curved sheet 208 andthe second curved sheet 208 are welded together by thefriction-stir-welding apparatus 247. The decoupling member 276 may alsotranslate but does not rotate relative to the first curved sheet 208 andthe second curved sheet 208. The decoupling member 276 may be at leastpartially positioned in a space 280 between the first magnetic member252 and the third magnetic member 264 and may move along the space 280.The decoupling member 276 is at least partially retained in the space280 by the first magnetic member 252 and the third magnetic member 264and may slidably engage at least one of the first magnetic member 252and the third magnetic member 264. In one aspect, the decoupling member276 slidably engages both the first magnetic member 252 and the thirdmagnetic member 264. In one example, the friction-stir-welding apparatus247 is also at least partially positioned in the space 280. A ballbearing or other device may be coupled between the decoupling member 276and the friction-stir welding apparatus 247 to allow the friction-stirwelding apparatus 247 to rotate relative to the decoupling member 276.The decoupling member 276 is guided along the space 280 by slidablyengaging edges of the first magnetic member 252 and the third magneticmember 264.

Referring to FIGS. 4, 10 and 12, in one example, the apparatus 212 alsoincludes a rigid joining member 284 coupled to the first curved sheet208 and to the second curved sheet 208 with the edge 256 of the firstcurved sheet 208 and the edge 256 of the second curved sheet 208abutting each other. In one aspect, the rigid joining member 284includes a curvature 286.

With reference to FIGS. 4-9, 12 and 13, in one example, the apparatus212 also includes the carriage 288 configured to move relative to thefirst curved sheet 208 and the second curved sheet 208. Thefriction-stir-welding apparatus 247 is coupled to and moveable with thecarriage 288. Additionally, the second magnetic member 260 and thefourth magnetic member 268 are coupled to and are moveable with thecarriage 288. Conversely, the first magnetic member 252 and thirdmagnetic member 264 remain stationary relative to the plurality ofcurved sheets 208.

Referring now to FIGS. 4-13 and 15, in one example of the presentdisclosure, the apparatus 212 is configured to constrain the edge 256 ofthe first curved sheet 208 and the edge 256 of the second curved sheet208. As described above, the apparatus 212 includes the first magneticmember 252 associated with the upper surface 216 of the first curvedsheet 208, the second magnetic member 260 associated with the lowersurface 220 of the first curved sheet 208, the third magnetic member 264associated with the upper surface 216 of the second curved sheet 208,and the fourth magnetic member 268 associated with the lower surface 220of the second curved sheet 208. The first magnetic member 252 ismagnetically coupled to the second magnetic member 260 and the thirdmagnet member 264 is magnetically coupled to the fourth magnetic member268 with the edge 256 of the first curved sheet 208 and the edge 256 ofthe second curved sheet 208 abutting each other.

With continued reference to FIGS. 4-13 and 15, in one example, the firstmagnetic member 252 and the second magnetic member 260 conform to thefirst curved sheet 208, and the third magnetic member 264 and the fourthmagnetic member 268 conform to the second curved sheet 208. The firstcurved sheet 208 and the second curved sheet 208 may have a wide varietyof shapes including, but not limited to, curved, flat, a combination ofcurved and flat, or any of a wide variety of shapes. Thus, the firstmagnetic member 252 and the second magnetic member 260 may be configuredto conform to any shape of the first curved sheet 208, and the thirdmagnetic member 264 and the fourth magnetic member 268 may be configuredto conform to any shape of the second curved sheet 208. In one aspect,at least two of the first magnetic member 252, the second magneticmember 260, the third magnetic member 264, and the fourth magneticmember 268 have a compliant shape. In one aspect, the first curved sheet208 and the second curved sheet 208 are curved metallic sheets 208. Insuch an aspect, the at least two of the first magnetic member 252, thesecond magnetic member 260, the third magnetic member 264, and thefourth magnetic member 268 (e.g., the first magnetic member 252 and thethird magnetic member 264) are compliant to the shapes of the curvedmetallic sheets 208.

With continued reference to FIGS. 4-13 and 15, in one example, the firstmagnetic member 252 and the second magnetic member 260 are locatedadjacent the edge 256 of the first curved sheet 208, and the thirdmagnetic member 264 and the fourth magnetic member 268 are locatedadjacent the edge 256 of the second curved sheet 208. In one aspect, thefirst magnetic member 252, the second magnetic member 260, the thirdmagnetic member 264, and the fourth magnetic member 268 comprisepermanent magnets. In another aspect, one of the first magnetic member252 and the second magnetic member 260 comprises a permanent magnet andanother of the first magnetic member 252 and the second magnetic member260 comprises a ferromagnetic material, and one of the third magneticmember 264 and the fourth magnetic member 268 comprises a permanentmagnet and another of the third magnetic member 264 and the fourthmagnetic member 268 comprises a ferromagnetic material. In anotheraspect, at least one of the first magnetic member 252 and the secondmagnetic member 260 comprises an electro-magnet, and at least one of thethird magnetic member 264 and the fourth magnetic member 268 comprisesan electro-magnet. In one aspect, the at least one electro-magnet isselectively activated and deactivated. In another aspect, the secondmagnetic member 260 and the fourth magnetic member 268 areelectro-magnets and the first magnetic member 252 and the third magneticmember 264 are one of an electro-magnet, a permanent magnet, or at leastpartially comprised of a ferromagnetic material.

Referring now to FIGS. 4 and 12-15, in one example, the apparatus 212also includes a joining member to be coupled to the first curved sheet208 and the second curved sheet 208. In one example, the joining memberis the flexible joining member 272 installed between one of the firstmagnetic member 252 and the third magnetic member 264 or the secondmagnetic member 260 and the fourth magnetic member 268 to provide acoupling between the first curved sheet 208 and the second curved sheet208 with the edge 256 of the first curved sheet 208 and the edge 256 ofthe second curved sheet 208 abutting each other. In one aspect, theflexible joining member 272 is installed between the first magneticmember 252 and the third magnetic member 264. In another aspect, theflexible joining member 272 is installed between the second magneticmember 260 and the fourth magnetic member 268.

With continued reference to FIGS. 4 and 12-15, in one example, theflexible joining member 272 includes adhesive 292 on at least a portionthereof, and the flexible joining member 272 is coupled to the firstcurved sheet 208 and the second curved sheet 208 with the adhesive 292.The adhesive 292 is located on the joining member 272 adjacent a firstedge 296 (see FIG. 12) and a second edge 300 (see FIG. 12) of thejoining member 272. The first edge 296 and the second edge 300 of theflexible joining member 272 oppose one another, with the first edge 296adhesively coupled to the first curved sheet 208 and the second edge 300adhesively coupled to the second curved sheet 208. In one example, theflexible joining member 272 includes a portion 304 lacking adhesive. Theportion 304 lacking adhesive is between the first edge 296 and thesecond edge 300 of the flexible joining member 272 and may at leastpartially overlap the edge 256 of the first curved sheet 208 and theedge 256 of the second curved sheet 208, with the edge 256 of the firstcurved sheet 208 and the edge 256 of the second curved sheet 208abutting each other.

With reference to FIGS. 10, 12 and 15, in one example, the joiningmember is a rigid joining member 284 and may be coupled to the firstcurved sheet 208 and the second curved sheet 208. The rigid joiningmember 284 may be coupled to the first curved sheet 208 and the secondcurved sheet 208 in a variety of ways, all of which are intended to bewithin the spirit and scope of the present disclosure. For example, therigid joining member 284 may be coupled to the first curved sheet 208and the second curved sheet 208 by at least one of fastening andwelding. In one aspect, the rigid joining member 284 is coupled to theupper surface 216 of the first curved sheet 208 and the upper surface216 of the second curved sheet 208. In another aspect, the rigid joiningmember 284 is coupled to the lower surface 220 of the first curved sheet208 and the lower surface 220 of the second curved sheet 208. The rigidjoining member 284 may include a slot 308 (see FIGS. 10 and 13) and mayinclude a curvature 286.

Referring to FIGS. 4, 10 and 12-15, in one example, the apparatus 212includes a first joining member and a second joining member. The firstjoining member and the second joining member are configured to becoupled to the first curved sheet 208 and the second curved sheet 208,with the edge 256 of the first curved sheet 208 and the edge 256 of thesecond curved sheet 208 abutting each other. In one example, the firstjoining member is the rigid joining member 284 and the second joiningmember is the flexible joining member 272.

With reference to FIGS. 4-13 and 15, in one example, the space 280 maybe provided between the first magnetic member 252 and the third magneticmember 264, and the apparatus 212 includes the joining member (one orboth joining members 272 and 284) coupled to the first curved sheet 208and the second curved sheet 208 and extending at least partially acrossthe space 280 between the first magnetic member 252 and the thirdmagnetic member 264. In one example, the apparatus 212 also includes thecarriage 288 configured to move relative to the first curved sheet 208and the second curved sheet 208. The second magnetic member 260 and thefourth magnetic member 268 are coupled to the carriage 288. The secondmagnetic member 260 and the fourth magnetic member 268 are configured tomove with the carriage 288 relative to the first curved sheet 208 andthe second curved sheet 208, and the first magnetic member 252 and thethird magnetic member 264 remain stationary relative to the first curvedsheet 208 and the second curved sheet 208.

Referring to FIGS. 13 and 15, in one example, the apparatus 212 alsoincludes at least one friction-reducing member 312. At least a portionof the at least one friction-reducing member 312 is between at least oneof the second magnetic member 260 and the fourth magnetic member 268 andat least one of the first curved sheet 208 and the second curved sheet208. In one aspect, the friction-reducing member 312 is a wheel 313. Aspacing 314 between a portion of the at least one of the second magneticmember 260 and the fourth magnetic member 268 and the at least one ofthe first curved sheet 208 and the second curved sheet 208 is maintainedwith the friction reducing member 312 engaging at least one of the firstcurved sheet 208 and the second curved sheet 208. In another aspect, thefriction-reducing member 312 is a layer 315 of material (e.g., hardplastic) applied to a surface of one of the second magnetic member 260and the fourth magnetic member 268. In one example, the apparatus 212may include a plurality of friction-reducing members 312. One of theplurality of friction reducing members 312 may be between the secondmagnetic member 260 and the first curved sheet 208 and another one ofthe plurality of friction-reducing members 312 may be between the fourthmagnetic member 268 and the second curved sheet 208. The apparatus 212may include any number of friction-reducing members 312 and any numberof friction-reducing members 312 may be between one of the magneticmembers and one of the curved sheets 208.

With reference to FIGS. 4, 9-13 and 15, in one example, the firstmagnetic member 252 includes a substrate 316 configured to engage theupper surface 216 of the first curved sheet 208 and the third magneticmember 264 includes a substrate 320 (see FIG. 10 configured to engagethe upper surface 216 of the second curved sheet 208. The substrate 316of the first magnetic member 252 is configured to conform to the firstcurved sheet 208 and the substrate 320 of the third magnetic member 264is configured to conform to the second curved sheet 208. The substrate316 of the first magnetic member 252 and the substrate 320 of the thirdmagnetic member 264 are flexible. The substrates 316 and 320 of thefirst magnetic member 252 and the third magnetic member 264,respectively, may be comprised of a variety of elements and/or materialsand all of such elements and/or materials are intended to be within thespirit and scope of the present disclosure. For example, the substrates316, 320 may be comprised of spring steel, plastic, rubber, metal,netting, mesh, etc. The substrates 316, 320 may also include one or moregrooves 324 (see FIG. 15) defined in a surface thereof. The grooves 324may be defined in the surface of the substrates 316, 320 that engagesthe curved sheet 208. The grooves 324 may assist the substrates 316, 320in conforming to the curved sheets 208 with which the substrates 316,320 engages. The grooves 324 may be defined in the surface of thesubstrates 316, 320 in any orientation such as, for example,longitudinal, transverse to a longitudinal extent of the substrates 316,320, diagonal, perpendicular to the longitudinal extent of thesubstrates 316, 320, etc. or a combination thereof. The grooves 324 mayalso have any of a wide variety of cross-sectional shapes taken along aplane perpendicular to a longitudinal extent of the grooves 324. Forexample, cross-sections of the grooves 324 may be, but not limited to,triangular, square, rectangular, polygonal, semi-circular, any arcuatelyperimetered shape, or any shape having a perimeter comprised of acombination of arcs and straight lines.

Referring to FIGS. 4, 9-13 and 15, in one example, the first magneticmember 252 includes a plurality of magnetic tiles 328 coupled to thesubstrate 316 of the first magnetic member 252, and the third magneticmember 264 includes a plurality of magnetic tiles 328 coupled to thesubstrate 320 of the third magnetic member 264. The plurality ofmagnetic tiles 328 coupled to the substrate 316 of the first magneticmember 252 are spaced apart from one another, and the plurality ofmagnetic tiles 328 coupled to the substrate 320 of the third magneticmember 264 are spaced apart from one another. The magnetic tiles 328 maybe comprised of permanent magnets, electromagnets, ferromagneticmaterial, or any other material have magnetic selectively magneticcharacteristics. Moreover, any number of magnetic tiles 328, includingone, may be coupled to each of the substrates 316 and 320 of the firstmagnetic member 252 and the third magnetic member 264, respectively. Inthe illustrated example, the magnetic tiles 328 are substantially squarein shape. However, the magnetic tiles 328 may have any shape including,but not limited to, rectangular, circular, ovular, triangular,polygonal, or any shape having an arcuate perimeter, a perimetercomprised of straight lines, or a perimeter comprised of both arcs andstraight lines. The magnetic tiles 328 may also be coupled to thesubstrates 316 and 320 of the first magnetic member 252 and the thirdmagnetic member 264 in a variety of ways including, but not limited to,bonding, fastening, fusing, unitary forming (as one-piece), or in anyother manners. The magnetic tiles 328 may also be spaced apart from oneanother at any distance. In one example, the magnetic tiles 328 arespaced-apart by about 0.02 inches (0.508 mm). In another example, themagnetic tiles 328 are spaced-apart by less than 0.25 inches (6.35 mm).In a further example, the magnetic tiles 328 are spaced-apart by lessthan 1 inch (25.4 mm). In still another example, the magnetic tiles 328are spaced-apart by less than 10 inches (254 mm). The magnetic tiles 328may also have a variety of sizes (e.g., height and length). In oneexample, the height of one of the tiles 328 may be about 0.75 inches(19.05 mm) and the length of one of the tiles 328 may be about 0.05inches (1.27 mm). In another example, the height of one of the tiles 328is less than 5 inches (127 mm) and the length of one of the tiles 328 isless than 5 inches (127 mm). In a further example, the height of one ofthe tiles 328 is less than 12 inches (304.8 mm) and the length of one ofthe tiles 328 is less than 12 inches (304.8 mm). The substrates 316, 320of the first magnetic member 252 and the third magnetic member 264 mayhave a variety of different thicknesses, any possibility of which isintended to be within the spirit and scope of the present disclosure. Inone example, the thickness of the substrates 316, 320 is about 0.01inches (0.254 mm). In another example, the thickness of the substrates316, 320 is less than 1 inch (25.4 mm). In a further example, thethickness of the substrates 316, 320 is less than 5 inches (127 mm).

With reference to FIGS. 3 and 16, one example of the present disclosurerelates to the vehicle 200, which includes the substructure 206 and aweldment 332 coupled to the substructure 206. The weldment 332 includesthe first sheet 208, the second sheet 208, and a butt weld 336 (see FIG.16) between the first sheet 208 and the second sheet 208. The butt weld336 is formed before the weldment 332 is coupled to the substructure206. In one aspect, the vehicle 200 is an airplane 200. In one aspect,the substructure 206 is at least a portion of the frame 204 of theairplane 200. In one aspect, the first sheet 208 is a first metallicfuselage sheet 208 and the second sheet 208 is a second metallicfuselage sheet 208. In one aspect, the first sheet 208 is one of a firstmetallic fuselage sheet 208, a first metallic wing sheet 208, and afirst metallic stabilizer sheet 208, and the second sheet 208 is asecond metallic fuselage sheet 208, a second metallic wing sheet 208,and a second metallic stabilizer sheet 208.

In FIGS. 4, 15 and 16, lines connecting various elements and/orcomponents of the vehicle 200 or the apparatus 212 may representmechanical, electrical, fluid, optical, electromagnetic and othercouplings and/or combinations thereof. Couplings other than thosedepicted in FIG. 3 may also exist. Dashed lines connecting the variouselements and/or components of the vehicle 200 or the apparatus 212 mayrepresent couplings similar in function and purpose to those representedby solid lines; however, couplings represented by the dashed lines areeither selectively provided or relate to alternative or optional aspectsof the disclosure. Likewise, elements and/or components of the vehicle200 or the apparatus 212 represented in dashed lines representalternative or optional aspects of the disclosure. Moreover, the absenceof lines between various elements and/or components of the vehicle 200or the apparatus 212 does not imply an absence of a relationship, anassociation, or a coupling between the elements and/or components of thevehicle 200 or the apparatus 212. Rather, a relationship, anassociation, and/or a coupling may be present between any of theelements and/or components of the vehicle 200 or the apparatus 212.

The following description pertains to examples of methods and processesassociated with the examples of vehicle and/or apparatuses described andillustrated in the figures. While particular steps and functionality aredescribed herein, such steps and functionality are merely examples andare not intended to be limiting. Rather, the vehicle and/or apparatusesare intended to include more, fewer, and different steps andfunctionality, and all of such possibilities are intended to be withinthe spirit and scope of the present disclosure.

An example of the present disclosure relates to a method ofmanufacturing an assembly including the first curved sheet 208 and thesecond curved sheet 208. In an example of the method, the first curvedsheet 208 includes a first upper surface 216 and a first edge 256, andthe second curved sheet 208 includes a second upper surface 216 and asecond edge 256. The method includes supporting the first upper surface216 and the second upper surface 216 (see FIG. 5), abutting the firstedge 256 and the second edge 256 so that the first upper surface 216 andthe second upper surface 216 are coextensive with a virtual arcuatesurface 236 (see FIG. 6), and welding the first edge 256 and the secondedge 256 together to create a weldment 332 after abutting the first edge256 and the second edge 256 (see FIG. 6). In one aspect, the virtualarcuate surface 236 includes no inflection points along a cross-sectionthereof perpendicular to a virtual straight line coextensive with thevirtual arcuate surface 236 (see FIGS. 6 and 7). In one example, themethod also includes constraining the first edge 256 and the second edge256 subsequent to abutting the first edge 256 and the second edge 256and prior to welding (see FIGS. 6 and 9-13).

In variant example, the method also includes reconfiguring tooling 232supporting the first upper surface 216 and the second upper surface 216.

In one aspect, the method also includes positioning a processing station248 to face a first lower surface 220 of the first curved sheet 208 anda second lower surface 220 of the second curved sheet 208 (see FIGS. 5-9and 12). In one variant, the method also includes moving the processingstation 248 relative to the first curved sheet 208 and the second curvedsheet 208. In one example of the method, positioning the processingstation 248 also includes positioning a friction-stir-welding apparatus247 to face the first lower surface 220 and the second lower surface220. In one example, the method also includes locating the firstmagnetic member 252 relative to the first upper surface 216 adjacent thefirst edge 256, locating the second magnetic member 260 relative to thefirst lower surface 220 adjacent the first edge 256, locating the thirdmagnetic member 264 relative to the second upper surface 216 adjacentthe second edge 256, locating the fourth magnetic member 268 relative tothe second lower surface 220 adjacent the second edge 256, andmagnetically coupling the first magnetic member 252 to the secondmagnetic member 260 and the third magnetic member 264 to the fourthmagnetic member 268 after abutting the first edge 256 and the secondedge 256 (see FIGS. 6, 7 and 9-13). In one example, the method alsoincludes coupling a flexible joining member 272 to the first curvedsheet 208 and to the second curved sheet 208 between at least one of thefirst magnetic member 252 and the third magnetic member 264 or thesecond magnetic member 260 and the fourth magnetic member 268 afterabutting the first edge 256 and the second edge 256 (see FIGS. 12-14).In one example of the method, the flexible joining member 272 is coupledto the first curved sheet 208 and the second curved sheet 208 betweenthe first magnetic member 252 and the third magnetic member 264 (seeFIGS. 12-14). In one variant, the method also includes decoupling theflexible joining member 272 from the first curved sheet 208 and thesecond curved sheet 208 (see FIGS. 13 and 14). In one example of themethod, decoupling also includes decoupling the flexible joining member272 from the first curved sheet 208 and the second curved sheet 208while welding the first edge 256 and the second edge 256 (see FIG. 14).In one aspect, the method also includes rotatably coupling a decouplingmember 276 to the friction-stir-welding apparatus 247 (see FIG. 14). Inone variant, the method also includes coupling a rigid joining member284 to the first curved sheet 208 and the second curved sheet 208 afterabutting the first edge 256 and the second edge 256 (see FIGS. 10 and13). In one aspect, the rigid joining member 284 includes a curvature286. In one example, the method also includes moving thefriction-stir-welding apparatus 247 relative to the first curved sheet208 and the second curved sheet 208. In one variant, the method alsoincludes moving the second magnetic member 260 and fourth magneticmember 268 relative to the first curved sheet 208 and the second curvedsheet 208.

In one example, the method also includes locating the first magneticmember 252 relative to at least one of the first upper surface 216 andthe second upper surface 216 adjacent at least one of the first edge 256and the second edge 256, locating the second magnetic member 260relative to at least one of a first lower surface 220 of the firstcurved sheet 208 and a second lower surface 220 of the second curvedsheet 208 adjacent at least one of the first edge 256 and the secondedge 256, and magnetically coupling the first magnetic member 252 to thesecond magnetic member 260 (see FIGS. 9-13). In one variant, the methodalso includes locating the first magnetic member 252 and the secondmagnetic member 260 relative to a same one of the first curved sheet 208and the second curved sheet 208 (see FIGS. 9-13).

In one aspect, the method also includes providing a space between thefirst edge 256 and the second edge 256 (see FIGS. 5 and 8) andprocessing at least one of the first edge 256 and the second edge 256(see FIG. 5). The space is sufficient to process at least one of thefirst edge 256 and the second edge 256. In one example of the method,abutting the first edge 256 and the second edge 256 occurs subsequent toprocessing at least one of the first edge 256 and the second edge 256(see FIG. 6).

In one variant of the method, supporting the first upper surface 216 andthe second upper surface 216 further includes coupling tooling 232 tothe first upper surface 216 and the second upper surface 216 (see FIGS.5-8). In one aspect, the method also includes moving the first curvedsheet 208 and the second curved sheet 208 relative to each other withthe tooling 232 (see FIGS. 5 and 6). In one example of the method,abutting also includes abutting the first edge 256 and the second edge256 with the tooling 232 (see FIG. 6).

In one aspect, the method also includes coupling the weldment 332 to astructure 206 (see FIGS. 3 and 16). In one example, the structure 206 isat least a portion of the frame 204 of an aircraft 200 (see FIGS. 3 and16).

In one variant, the method also includes processing the weldment 332(see FIG. 7). In one aspect of the method, processing the weldment 332includes performing gauge reduction on at least a portion of theweldment 332. In another example of the method, processing the weldment332 includes reducing the thickness of at least a portion of theweldment 332. In another aspect of the method, processing the weldment332 includes trimming at least a portion of the weldment 332.

As realized herein, a variety of different aspects, examples, andvariants of the apparatus and methods are disclosed herein that includea variety of components, features, and functionality. It should beunderstood that the various aspects, examples, and variants of theapparatus and methods disclosed herein are capable of including any ofthe components, features, and functionality of any of the other aspects,examples, and alternatives of the apparatus and methods disclosed hereinin any combination, and all of such possibilities are intended to bewithin the spirit and scope of the present disclosure. The terms“aspect”, “example” and “variant” hereinabove are used interchangeably.

Many modifications and other examples of the disclosure set forth hereinwill come to mind to one skilled in the art to which the disclosurepertains having the benefit of the teachings presented in the foregoingdescriptions and the associated drawings.

Therefore, it is to be understood that the disclosure is not to belimited to the specific embodiments disclosed and that modifications andother embodiments are intended to be included within the scope of theappended claims. Moreover, although the foregoing descriptions and theassociated drawings describe example embodiments in the context ofcertain illustrative combinations of elements and/or functions, itshould be appreciated that different combinations of elements and/orfunctions may be provided by alternative implementations withoutdeparting from the scope of the appended claims.

The Abstract of the disclosure is provided to allow the reader toquickly ascertain the nature of the technical disclosure. It issubmitted with the understanding that it will not be used to interpretor limit the scope or meaning of the claims. In addition, in theforegoing Detailed Description, it can be seen that various features aregrouped together in various embodiments for the purpose of streamliningthe disclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter lies in less than allfeatures of a single disclosed embodiment. Thus, the following claimsare hereby incorporated into the Detailed Description, with each claimstanding on its own as a separately claimed subject matter.

What is claimed is:
 1. An apparatus for manipulating a plurality ofcurved sheets, wherein the plurality of curved sheets comprises a firstcurved sheet and a second curved sheet, wherein the first curved sheetcomprises a first upper surface, a first lower surface, and a firstedge, and wherein the second curved sheet comprises a second uppersurface, a second lower surface, and a second edge, the apparatuscomprising: a housing; first holders extending from the housing in afirst direction, wherein the first holders are configured to beremovably coupled to the first upper surface of the first curved sheet,and wherein the first holders are individually movable along the firstdirection to position the first curved sheet such that the first uppersurface is coextensive with a first portion of a virtual arcuatesurface; second holders extending from the housing in a seconddirection, wherein the second holders are configured to be removablycoupled to the second upper surface of the second curved sheet, andwherein the second holders are individually movable along the seconddirection to position the second curved sheet such that the second uppersurface is coextensive with a second portion of the virtual arcuatesurface and such that the second edge is abutting the first edge; acarriage disposed in a facing relationship with the first lower surfaceof the first curved sheet and the second lower surface of the secondcurved sheet, wherein the carriage is operable to move along the firstedge and the second edge of the first curved sheet and the second curvedsheet when the first edge and the second edge are abutting one another;a processing station coupled to the carriage, wherein the processingstation is movable with the carriage, and wherein the processing stationcomprises a welding apparatus operable to weld the first edge and thesecond edge as the carriage moves along the first edge of the firstcurved sheet and along the second edge of the second curved sheet whenthe first edge and the second edge are abutting one another; a firstmagnetic member, configured to be positioned on the first upper surfaceof the first curved sheet adjacent the first edge; a second magneticmember coupled to the carriage, wherein the second magnetic membermagnetically couples to the first magnetic member when the firstmagnetic member is positioned on the first upper surface of the firstcurved sheet, and wherein the second magnetic member is movable with thecarriage; a third magnetic member, configured to be positioned on thesecond upper surface of the second curved sheet adjacent the secondedge, and a fourth magnetic member coupled to the carriage, wherein thefourth magnetic member magnetically couples to the third magnetic memberwhen the third magnetic member is positioned on the second upper surfaceof the second curved sheet, and wherein the fourth magnetic member ismovable with the carriage.
 2. The apparatus of claim 1, wherein thevirtual arcuate surface includes no inflection points along across-section thereof perpendicular to a virtual straight linecoextensive with the virtual arcuate surface.
 3. The apparatus of claim1, wherein the plurality of curved sheets, abutted so that uppersurfaces of the plurality of curved sheets are coextensive with thevirtual arcuate surface, subtend a central angle between about 2 degreesand about 270 degrees in a virtual plane perpendicular to a virtualstraight line coextensive with the virtual arcuate surface.
 4. Theapparatus of claim 1, further comprising a flexible joining member,configured to be installed between the first magnetic member and thethird magnetic member or between the second magnetic member and thefourth magnetic member to provide a coupling between the first curvedsheet and the second curved sheet with the first edge of the firstcurved sheet and the second edge of the second curved sheet abuttingeach other.
 5. The apparatus of claim 4, wherein the welding apparatuscomprises a friction-stir-welding apparatus, and wherein the apparatusfurther comprising a decoupling member rotatably attached to thefriction-stir-welding apparatus to eliminate the coupling provided bythe flexible joining member between the first curved sheet and thesecond curved sheet.
 6. The apparatus of claim 1, further comprising arigid joining member, configured to be installed between the firstmagnetic member and the third magnetic member or between the secondmagnetic member and the fourth magnetic member to provide a couplingbetween the first curved sheet and the second curved sheet with thefirst edge of the first curved sheet and the second edge of the secondcurved sheet abutting each other.
 7. The apparatus of claim 1, furthercomprising: a flexible joining member, configured to be installedbetween one of the first magnetic member and the third magnetic memberor the second magnetic member and the fourth magnetic member to providea first coupling between the first curved sheet and the second curvedsheet with the first edge of the first curved sheet and the second edgeof the second curved sheet abutting each other; and a rigid joiningmember, configured to be installed between a remaining one of the firstmagnetic member and the third magnetic member or the second magneticmember and the fourth magnetic member to provide a second couplingbetween the first curved sheet and the second curved sheet with thefirst edge of the first curved sheet and the second edge of the secondcurved sheet abutting each other.
 8. The apparatus of claim 1, furthercomprising: a first friction-reducing member disposed between the secondmagnetic member and the first lower surface of the first curved sheet;and a second friction-reducing member disposed between the fourthmagnetic member and the second lower surface of the second curved sheet.9. The apparatus of claim 8, wherein the first friction-reducing memberand the second friction-reducing member comprise wheels.
 10. Theapparatus of claim 9, wherein the first friction-reducing member and thesecond friction-reducing member comprise layers of material applied torespective surfaces of the second magnetic member and the fourthmagnetic member.
 11. The apparatus of claim 9, wherein the firstfriction-reducing member maintains a first spacing between the secondmagnetic member and the first lower surface of the first curved sheet,and wherein the second friction-reducing member maintains a secondspacing between the fourth magnetic member and the second lower surfaceof the second curved sheet.
 12. The apparatus of claim 1, wherein theplurality of curved sheets further comprises a third curved sheet,wherein the third curved sheet comprises a third upper surface, a thirdlower surface, and a third edge, and wherein the second curved sheetcomprises a fourth edge, the apparatus further comprising: third holdersextending from the housing in a third direction, wherein the thirdholders are configured to be removably coupled to the third uppersurface of the third curved sheet, and wherein the third holders areindividually movable along the third direction to position the thirdcurved sheet such that the third upper surface is coextensive with athird portion of the virtual arcuate surface and such that the thirdedge is abutting the fourth edge; a fifth magnetic member, configured tobe positioned on the third upper surface of the third curved sheetadjacent the third edge; a sixth magnetic member, configured to bepositioned on the second upper surface of the second curved sheetadjacent the fourth edge; wherein the carriage is further operable to:translate from the first edge and the second edge that have been weldedto a location of the third edge of the third curved sheet and the fourthedge of the second curved sheet when the third edge and the fourth edgeare abutting one another such that the second magnetic member couples tothe fifth magnetic member and the fourth magnetic member couples to thesixth magnetic member; and move along the third edge of the third curvedsheet and the fourth edge of the second curved sheet when the third edgeand the fourth edges are abutting one another, and wherein the weldingapparatus is further operable to weld the third edge and the fourth edgeas the carriage moves along the third edge and the fourth edge, abuttingone another.
 13. The apparatus of claim 1, wherein the plurality ofcurved sheets comprises a third curved sheet, wherein the third curvedsheet comprises a third upper surface, a third lower surface, and athird edge, and wherein the second curved sheet comprises a fourth edge,the apparatus further comprising: third holders extending from thehousing in a third direction, wherein the third holders are configuredto be removably coupled to the third upper surface of the third curvedsheet, and wherein the third holders are individually movable along thethird direction to position the third curved sheet such that the thirdupper surface is coextensive with a third portion of the virtual arcuatesurface and such that the third edge is abutting the fourth edge;wherein the first magnetic member is further configured to be positionedon the third upper surface of the third curved sheet adjacent the firstedge; wherein the third magnetic member is further configured to bepositioned on the second upper surface of the second curved sheetadjacent the fourth edge; wherein the carriage is further operable to:translate from the first edge and the second edge that have been weldedto a location of the third edge of the third curved sheet and the fourthedge of the second curved sheet when the third edge and the fourth edgeare abutting one another such that the second magnetic member couples tothe first magnetic member and the fourth magnetic member couples to thethird magnetic member; and move along the third edge of the third curvedsheet and the fourth edge of the second curved sheet when the third edgeand the fourth edge are abutting one another; and wherein the weldingapparatus is further operable to weld the third edge and the fourth edgeas the carriage moves along the third edge and the fourth edge, abuttingone another.
 14. The apparatus of claim 1, wherein the first magneticmember comprises a first plurality of magnetic tiles coupled to a firstflexible substrate, and wherein the third magnetic member comprises asecond plurality of magnetic tiles coupled to a second flexiblesubstrate.
 15. An apparatus for manipulating a plurality of curvedsheets, wherein the plurality of curved sheets comprises a first curvedsheet and a second curved sheet, wherein the first curved sheetcomprises a first upper surface, a first lower surface, and a firstedge, and wherein the second curved sheet comprises a second uppersurface, a second lower surface, and a second edge, the apparatuscomprising: a housing; first holders extending from the housing in afirst direction, wherein the first holders are configured to beremovably coupled to the first upper surface of the first curved sheet,and wherein the first holders are individually movable along the firstdirection to position the first curved sheet in a first position or in asecond position, wherein the first upper surface of the first curvedsheet is coextensive with a first portion of a virtual arcuate surfacein the second position; second holders extending from the housing in asecond direction, wherein the second holders are configured to beremovably coupled to the second upper surface of the second curvedsheet, and wherein the second holders are individually movable along thesecond direction to position the second curved sheet in a third positionor in a fourth position, wherein the second edge of the second curvedsheet is spaced apart from the first edge when the first curved sheet isin the first position and the second curved sheet is in the thirdposition, wherein the second upper surface of the second curved sheet iscoextensive with a second portion of the virtual arcuate surface in thefourth position, and wherein the first edge is abutting the second edgewhen the first curved sheet is in the second position and the secondcurved sheet is in the fourth position; a carriage disposed in a facingrelationship with the first lower surface of the first curved sheet andthe second lower surface of the second curved sheet, wherein thecarriage is operable to move along the first edge of the first curvedsheet and the second edge of the second curved sheet when the firstcurved sheet and the second curved sheet are, respectively, in thesecond position and the fourth position; a processing station coupled tothe carriage, wherein the processing station is movable with thecarriage along the first edge of the first curved sheet and the secondedge of the second curved sheet when the first curved sheet and thesecond curved sheet are, respectively, in the second position and thefourth position, and wherein the processing station comprises: asubtractive-manufacturing apparatus operable to process one of the firstedge and the second edge when the first curved sheet is in the firstposition and the second curved sheet is in the third position; and awelding apparatus operable to weld the first edge and the second edge asthe carriage moves along the first edge and the second edge when thefirst curved sheet and the second curved sheet are, respectively, in thesecond position and the fourth position and the first edge and thesecond edge abut each other; a first magnetic member, configured to bepositioned on the first upper surface of the first curved sheet adjacentthe first edge; a second magnetic member coupled to the carriage,wherein the second magnetic member magnetically couples to the firstmagnetic member when the first magnetic member is positioned on thefirst upper surface of the first curved sheet, and wherein the secondmagnetic member is movable with the carriage; a third magnetic member,configured to be positioned on the second upper surface of the secondcurved sheet adjacent the second edge; and a fourth magnetic membercoupled to the carriage, wherein the fourth magnetic member magneticallycouples to the third magnetic member when the third magnetic member ispositioned on the second upper surface of the second curved sheet, andwherein the fourth magnetic member is movable with the carriage.
 16. Theapparatus of claim 15, wherein the first magnetic member is configuredto be positioned on the first upper surface of the first curved sheetafter the first holders move the first curved sheet to the secondposition, and wherein the second magnetic member is configured to bepositioned on the second upper surface of the second curved sheet afterthe second holders move the second curved sheet to the fourth position.17. The apparatus of claim 15, further comprising a flexible joiningmember, configured to be installed between the first magnetic member andthe third magnetic member or between the second magnetic member and thefourth magnetic member after the first curved sheet and second curvedsheet are moved to the second position and the fourth position,respectively, to provide a coupling between the first curved sheet andthe second curved sheet with the first edge of the first curved sheetand the second edge of the second curved sheet abutting each other. 18.The apparatus of claim 17, wherein the welding apparatus comprises afriction-stir-welding apparatus, and wherein the apparatus furthercomprising a decoupling member rotatably attached to thefriction-stir-welding apparatus to eliminate the coupling provided bythe flexible joining member between the first curved sheet and thesecond curved sheet.
 19. The apparatus of claim 15, further comprising arigid joining member, configured to be installed between the firstmagnetic member and the third magnetic member or between the secondmagnetic member and the fourth magnetic member after the first curvedsheet and the second curved sheet are moved to the second position andthe fourth position, respectively, to provide a coupling between thefirst curved sheet and the second curved sheet with the first edge ofthe first curved sheet and the second edge of the second curved sheetabutting each other.
 20. The apparatus of claim 15, further comprising:a flexible joining member, configured to be installed between one of thefirst magnetic member and the third magnetic member or the secondmagnetic member and the fourth magnetic member after the first curvedsheet and the second curved sheet are moved to the second position andthe fourth position, respectively, to provide a first coupling betweenthe first curved sheet and the second curved sheet with the first edgeof the first curved sheet and the second edge of the second curved sheetabutting each other; and a rigid joining member, configured to beinstalled between a remaining one of the first magnetic member and thethird magnetic member or the second magnetic member and the fourthmagnetic member after the first curved sheet and the second curved sheetare moved to the second position and the fourth position, respectively,to provide a second coupling between the first curved sheet and thesecond curved sheet with the first edge of the first curved sheet andthe second edge of the second curved sheet abutting each other.